Foam in the floor

Those styrofoam floors have some benefits.....shaves quite a bit of weight, insulation value and doesn't rot.

It's biggest negative....you can leave trails in it.

I can’t remember off the top of my head what the name was, but I found a you tube video from a guy that had an epoxy resin that he pumped into the floor. He let it set, smoothed it off and recovered it. Looked like it worked but I have no personal experience with it.

I would not worry about it. But, that is just me and I'm a Caveman.

All reasonable responses but the decision comes down to how much time, money and effort do you want to spend on a 9 year old TT.

Our TT is 10 years old and we have yet to find a new unit we like. So chances are we would repair or live with the issue.

Good luck

When I did a repair like this, I cut back to the nearest supports. You could also add joists underneath to tie back into. I used thinner foam and thicker plywood to make the repair.
As long as you have solid support under the edges of the repair area, it will be fine.
Really, replacing the vinyl flooring is the biggest pain. In the end, I just put a small area rug over it.

Best option is to trade it in for a trailer with a plywood floor. Next option is to cover the entire floor with plywood like it should have been in the first place.

put it out of your mind.

pull it up level and put down very nice carpet squares they,ll move with the floor some very nice higher end ones you,ll never no there down.

New trailer, or if you have payload capacity to spare you could try self leveling compound and putting linoleum over it to level the floor. Replacing the flooring isn't really an option IMHO since they're integral to how the trailer functions. I've seen some Airstream frame off restorations to redo the flooring and even though they're made about an order of magnitude more stoutly than your typical TT they're still unbelievably fragile when not tied into the flooring, they're also worth a lot more so it's easier to justify the extreme labor cost.